Abstract

Sepsis is an inflammatory disease with exacerbated inflammation at early stages. Inflammatory cytokines play critical roles in the pathophysiology of sepsis. Ubiquitin-specific peptidase 18 (USP18), a deubiquitinating enzyme, has been shown to modulate transforming growth factor-β-activated kinase 1 (TAK1) activity. However, the precise role of USP18 in sepsis is not clear. Here, we investigated the potential effect of USP18 on inflammation in sepsis. We generated mice with USP18 or/and TAK1 deficiency in macrophages (USP18^MKO mice, TAK1^MKO mice and USP18^MKO-TAK1^MKO mice) and established a lipopolysaccharide (LPS)-induced sepsis model in mice. Bone marrow-derived macrophages were isolated from wild-type (WT), USP18^MKO or TAK1^MKO mice and treated with LPS or CpG, and the expression of cytokines including IL-6, IL-10, IL-1β and tumor necrosis factor α (TNF-α) was measured. The activation of NF-κB, ERK and p38 signaling pathways and ubiquitination of TAK1 were detected. We induced sepsis in WT, USP18^MKO, TAK1^MKO or USP18^MKO-TAK1^MKO mice and evaluated the survival rate, lung pathology and inflammatory cytokine levels in serum. Macrophages deficient in USP18 produced significantly increased IL-6, IL-1β and TNF-α post-LPS or -CpG stimulation. Macrophages deficient in USP18 had promoted activation of NF-κB, p38 and ERK, and increased ubiquitination of TAK1. Mice with TAK1 deficiency in macrophages had increased survival rates, decreased immune cell infiltration in lung and decreased pro-inflammatory cytokines in serum. In contrast, mice with USP18 deficiency in macrophages had decreased survival rates, increased cell infiltration in lung and increased pro-inflammatory cytokines in serum. USP18 alleviated LPS-induced sepsis by inhibiting TAK1 activity.

中文翻译：

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泛素特异性肽酶 18 通过靶向转化生长因子-β-激活激酶 1 活性负向调节和抑制脂多糖诱导的败血症

摘要

脓毒症是一种炎症性疾病，早期炎症加重。炎性细胞因子在脓毒症的病理生理学中起着关键作用。泛素特异性肽酶 18 (USP18) 是一种去泛素化酶，已被证明可以调节转化生长因子-β-激活激酶 1 (TAK1) 的活性。然而，USP18 在脓毒症中的确切作用尚不清楚。在这里，我们研究了 USP18 对脓毒症炎症的潜在影响。我们生成了巨噬细胞缺乏 USP18 或/和 TAK1 的小鼠（USP18 ^MKO小鼠、TAK1 ^MKO小鼠和 USP18 ^MKO -TAK1 ^MKO小鼠），并在小鼠中建立了脂多糖 (LPS) 诱导的败血症模型。骨髓来源的巨噬细胞分离自野生型 (WT)、USP18 ^MKO或TAK1 ^MKO小鼠并用LPS或CpG处理，并测量细胞因子包括IL-6，IL-10，IL-1β和肿瘤坏死因子α（TNF-α）的表达。检测到 NF-κB、ERK 和 p38 信号通路的激活以及 TAK1 的泛素化。我们在 WT、USP18 ^MKO、TAK1 ^MKO或 USP18 ^MKO -TAK1 ^{MKO中诱导败血症}小鼠并评估血清中的存活率、肺病理学和炎性细胞因子水平。USP18 缺陷的巨噬细胞在 LPS 或 -CpG 刺激后产生显着增加的 IL-6、IL-1β 和 TNF-α。USP18 缺陷的巨噬细胞促进了 NF-κB、p38 和 ERK 的激活，并增加了 TAK1 的泛素化。巨噬细胞缺乏 TAK1 的小鼠存活率增加，肺部免疫细胞浸润减少，血清中促炎细胞因子减少。相比之下，巨噬细胞缺乏 USP18 的小鼠存活率降低，肺部细胞浸润增加，血清中促炎细胞因子增加。USP18 通过抑制 TAK1 活性减轻 LPS 诱导的败血症。